The present invention relates generally to a safety syringe, and more particularly to a restrictively rotatable plunger of the safety syringe.
The conventional syringe comprises a barrel and a plunger which is disposed in the barrel in such a manner that the plunger can be turned without limitation in relation to the barrel. However, there are currently a variety of safety syringes, which comprise a restrictively rotatable plunger so as to facilitate the catching of the needle holder by the plunger. The restrictive rotation of the plunger is attained by a single control method which is limited in its application. In addition, the conventional structures are complicated in construction and can not be easily assembled. Moreover, the conventional structures do not work properly.
It is the primary objective of the present invention to provide a safety syringe with a plunger which can be turned restrictively with certainty.
It is another objective of the present invention to provide a safety syringe with a structure which is designed to enable a plunger of the safety syringe to be turned with limitation and can be easily assembled at low cost.
It is still another objective of the present invention to provide a safety syringe with a plunger rotating structure which is simple in construction and can be operated with ease.
The present invention comprises a barrel having a grip log, two fitting holes and two retaining holes; an elastic lashing member capable of retracting elastically and having two locating pillars which are provided at the top end with an arresting head. The arresting head is fitted with the fitting hole. The locating pillars are retained in the retaining holes of the barrel. Two sliding and confining portions are respectively disposed in the opposite inner sides of the bases such that they form inwardly a slide slot; a plunger having two slide pieces, a rear rod body connected with the rear segment of the front rod body, a rotation confining portion disposed at the front end thereof; a needle holder having a cooperating portion to be caught by the rotation confining portion of the plunger, a needle connection portion for fitting the needle set.
In use, the slide pieces of the plunger are confined by the slide portion of the elastic lashing member and can not be turned. Upon completion of injection, which the plunger is arrived at the bottom, the plunger is not confined by the elastic lashing member and can be thus turned to actuate the needle holder, which is then drawn into the barrel by the plunger.